Cochlear implantation (CI) was approved by medical device administration agencies about 35 years ago, and it is now established as one of the most important interventions for severe and profound sensorineural hearing loss. While cochlear implants give much less sound information to the patient than the normal auditory pathway, it yields tremendous outcomes in relation to the speech perception of patients. This is because cochlear implants stimulate the patient's auditory pathway and positively changes its structure and function, which is not observed with conventional auditory interventions. Moreover, many issues regarding the anatomy and physiology of the auditory pathway have emerged with the extended indications for CI, including bilateral implantation, hearing preservation surgery, and implantation for cases with single-sided deafness or cochlear anomalies. Thus, a much deeper understanding of the auditory pathway is necessary so that more efficient techniques of surgery or mapping can be established and better outcomes of CI achieved.
In this review, I present the findings of some cutting-edge research on the auditory pathway and CI conducted using molecular biological, genetic, or functional brain imaging techniques, as well as established knowledge on the auditory pathway.
[Objective] To report the results of trial use of hearing-aids (HAs) in elderly individuals attending an adult day-care center. [Participants] The subjects were 38 elderly individuals with a hearing loss of 35dB HL or over in the better ear (male 17, female 21; 46.5 ± 9.2dB; 83.7 ± 6.7 years old; MMSE 24.6 ± 6.0; FIM 47-125). Seven of the subjects were already wearing their own HAs (pre-use group).
[Methods] Trial use of a Bhind-the-Ear hearing aid in one ear was proposed to 31 participants. The trial period was 3 months.
[Results] Nine out of the 31 subjects accepted the proposal (acceptance group), seven continued wearing their HAs, and five purchased their own HAs. The pre-use group (n=7) had more severe hearing loss as compared to the other groups, however, there was no significant difference between the acceptance (n=9) and non-acceptance (n=22) groups. The former group was more strongly aware of difficulty under bad conditions than the latter. The effect of HAs was evident not only in the perception of speech sounds, but also in that of environmental sounds or supra-segmental elements of speech. Cases of aphasia with limited language ability (n=3) showed improved emotional stability and daily communication.
[Conclusion] The findings of this study showed the importance of hearing screening and HA intervention for the elderly attending adult-day-care centers. Factors related to non-acceptance of HAs need to be clarified.
Recently, attention has been focused on the psychological changes observed in aged patients receiving cochlear implantation, as the number of cases of cochlear implantation is increasing in Japan. In this report, we investigated the changes observed in the depressive tendency and anxiety in of aged patients receiving cochlear implantation using the Self-rating Depression Scale (SDS) and State-Trait Anxiety Inventory (STAI). The results revealed no significant change in the depressive tendency or anxiety after the procedure. Next, we divided the patients into two groups according to the post-operative hearing ability. A tendency towards increase in the depressive tendency and anxiety was observed in the patients who achieved a higher hearing ability.
These results suggest that we need to pay careful attention to the risk of depression after cochlear implantation in aged patients, even if they acquire better hearing ability after the cochlear implantation. Moreover, our results suggest the clinical usefulness of evaluation using the SDS and STAI before and after cochlear implantation for rehabilitation, considering the potential for psychological changes in the patients.
We performed a speech perception experiment using CI 2004 monosyllable lists and 67-S lists in Cochlear Implant (CI) users [n=19], to evaluate the effects of different monosyllable lists on the test outcomes. The results showed that average speech perception reached 61.0% with the CI 2004 list and 78.0% with the 67-S list, the latter providing significantly better speech recognition. Comparison of between the common monosyllable lists revealed an average level of 62.6% for CI 2004 and an average of 74.6% for 67-S, the difference not being statistically significant. Statistical analysis of the test results showed no significant differences in speech perception for presentation levels in the range of 40dBHL to across various presentation levels (40, 50, 55, 60, and 70dB HL)
Speech perception tests involve auditory psychophysics. The presentation level, type and number of monosyllables, and differences in spoken stimuli can influence the test performance. This study showed that only the type of monosyllabic words influenced the results. As there is no standardized approach for the assessment of CI recipients in Japan, it would be important that scientists and academic societies work together to create assessment guidelines for effective and comparable hearing assessment methods.
With the widespread implementation of newborn hearing screening (NHS) in Japan, earlier diagnosis of mild to moderate, as well as severe to profound, congenital hearing loss (HL) has become possible. The genetic causes of HL in many cases have been identified even in early childhood by genetic testing for HL. We identified mutations in the USH2A gene that cause Usher syndrome, type 2 (USH2), in three siblings under 10 years old, by massively parallel DNA sequencing analysis. All the three children have non-progressive moderate to severe sensorineural HL with a high-frequency sloping configuration, which is the typical hearing pattern of USH2. None has exhibited any vestibular symptoms or visual abnormalities until now. USH2 cases usually have normal vestibular function, and onset of retinitis pigmentosa (RP) usually occurs in the second decade of life or later; we diagnosed all the children as having USH2. We could provide genetic counseling on the risk of future visual disturbance and the applicable educational support to these patients and their families. Early diagnosis of syndromic HL by genetic testing may be useful, in addition to the NHS program, for appropriate clinical management and educational guidance.
This study on the effects of early interventions for hearing-impaired infants (0-2 years old) was conducted with the participation of 100 special-needs education schools for the deaf in Japan.
Most infants received a diagnosis of hearing loss after a newborn hearing screening test (NHS), and 1,831 infants went to schools for the deaf for consultation in 2017. The percentage of infants with mild to moderate hearing impairment was 38%, and that of infants with other disorders (e.g., cognitive disorders) was 23%. The percentage of deaf infants with a cochlear implant (CI) was 19% (including many 0-year-old infants with binaural CI, and many 2-year-old infants with bilateral CI). Daily use of hearing aids (HAs) is difficult in infants, and only a half of them wore HAs for more than 4 hours a day.
For educational activities, the total communication method was used in 75% of the schools, and multiple regression analysis revealed no significant correlation between the number of infants with CI (s) and the use of auditory-oral communication.
Intervention programs for infants were conducted in group and individual styles, about twice a month for each style, and the frequency of therapy gradually increased in the group of 2-year-old infants relative to the group of 0-year-old in fants. The beneficial effects of early interventions in the schools (e.g., support for families, toddlers, teachers, and social cooperation) were suggested by teachers who responded to this survey.
At present, NHS is implemented widely throughout the country, and the results of our survey suggest that social support systems for early intervention programs for infants' development after early diagnosis of hearing loss are needed, based on the prevalence of hearing loss.
Hyperacusis is an auditory disorder in which sounds of normal volume are perceived as being too loud or even painfully loud. There are some different varieties of hyperacusis other than tinnitus that occur even in the absence of loud environmental sounds or autophony, that arise with one's own voice. There are various kinds of concrete expressions for describing hyperacusis symptoms, such as “ringing”, “bigger or louder” and “cracked”, however, the clinical significance of distinguishing among these expressions remains unclear. Therefore, we analyzed the expressions used to describe the symptoms of hyperacusis and their clinical significance in 168 patients. Of the 168 patients, 113 had a history of sudden sensorineural hearing loss, 24 had age-related hearing loss, 12 patients had normal hearing function, and the remaining 19 had other kinds of ear diseases. The most frequent complaint was “ringing”. Therefore, “ringing” may represent a typical nonspecific expression of hyperacusis. Descriptions such as “cracked” and “doubling” were more frequent in the group of patients with hearing loss than in the normal hearing group. However, the expression “bigger or louder” was particularly more frequent in the normal hearing group than in the group with hearing loss. We believe that these differences serve to highlight the different pathologies underlying the development of so-called hyperacusis.
[Objective] In this study, we investigated the hearing levels of elderly individuals attending an adult day-car center.
[Subjects and Methods] Ear examinations, audiometry and a questionnaire survey on the self-awareness of hearing loss were performed in 74 attendees of an adult day-care center (males 42, females 32; 78±8.1 years old; MMSE 25.5±5.3; FIM 103.1±17.8).
[Results] The ear examinations revealed cerumen impaction in 22 subjects (30%), of which, in 7, the impacted cerumen could not be removed. The pure-tone audiometry threshold could be obtained in all the subjects. Bilateral hearing loss was observed in 58 subjects (78%; mild 31, moderate 27). There was a moderate correlation between the hearing level and age. Dropping a beanbag or pushing a button on a desk were useful as response to the stimulus sounds in audiometry. The MMSE scores of those who used the beanbag method were significantly lower than those of the subjects who used the standard method or the button on a desk method. The answers to the questionnaire revealed that those with moderate hearing loss and their families noticed the hearing disability more clearly than those with mild hearing loss and their families.
[Discussion] Removal of cerumen and an appropriately selected reaction according to cognitive function seemed to be important to obtain useful results of audiometry. Auditory compensation with hearing aids may be provided to those with moderate hearing loss.
Introduction: We studied the effects of cochlear implantation in elderly patients, the problems in the rehabilitation of these patients, and methods of support that might be useful, based on investigation of the speech-language-hearing therapists in charge.
Methods: An anonymous self-reported questionnaire survey was conducted; the questionnaire was mailed to 103 speech-language-hearing therapists belonging to cochlear implantation surgery facilities in Japan.
Result: The questionnaires were answered by and received from 32 therapists. The answers showed that the conversations between the families and speech-language-hearing therapists improved with cochlear implantation. The characteristics and problems associated with the rehabilitation of these patients included difficulties of device operation and management, such as sound quality evaluation, program switching, volume adjustment, and cable exchange. In particular, many respondents indicated that the frequency of such problems was higher with subjects who were ≥75 years than with those who were 64-74 years old. We extracted the following 6 categories by analysis of the free descriptive answers: “difficulty in the rehabilitation scene,” “an individual's characteristics and establishment of a network,” “social and cognitive programs because of aging,” “necessity of used cochlear implant,” “individual differences,” and “anxiety about continuing rehabilitation.”
Conclusion: To rehabilitate elderly patients with cochlear implants, the physical and cognitive abilities of the individuals must be recognized. Longitudinal and individual rehabilitative support systems are needed for elderly patients with cochlear implants.